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Rh far in the way of replacing the actual luminous effects. The writer offers the following prefatory observations in regard to some points of his work:

In regard to the experiments described, there are two things to be said. It would have been desirable, if possible, to have stated the originator of every experiment; but it was not possible. Attempt has been made to indicate, as far as known, the first to employ any striking very recent experiment; but many of great beauty seem now such common property that it is difficult to ascertain who first made them, or first adapted them for projection. I strongly suspect that we owe to Professor Tyndall many more than it has been possible categorically to ascribe to him; and am the more anxious to state this, because his just claims in higher matters appear to me almost studiously ignored by certain Continental physicists. Some arrangements are, to the best of my belief, original; but none are put forth as such except one or two expressly stated, and it should be perfectly understood that no personal claim is implied regarding any other experiments because no credit is given to some one else; the absence of such credit is simply due to sheer ignorance and the difficulty of acquiring knowledge concerning such matters.

The other remark is, that the order of the experiments differs considerably in some cases from that usually adopted. All that can be said upon that point is, that such is the result of considerable reflection, and in the belief that the order chosen is, upon the whole, best adapted to the primary end of assisting vivid conception of the physical realities considered and the relation of the phenomena to one another. Also, while no attempt is made to arrange the experiments in set "lectures," the order followed is believed to lend itself best to such a connected course of experimental lectures as a teacher would desire to give to his class, extended or abridged as the case may require. I am not without hope that, in such an extended course of experiments as are here collected for his choice, some hard-worked teacher may find real help in this respect. The same may be said as to the brief references made to the connection between the phenomena of light and the problems of molecular physics. Brief as they are, it is hoped they may in some minds excite a real interest in those problems, and deepen that sense of the reality of the phenomena which is so desirable.

founder and head of the distinguished publishing house of Macmillan & Co., was a man of mark, of strong character, rare business talents, a man of ideas, a deeply religious man, who yet got free of the trammels of theology, and a life-long victim of pulmonary disease, which ended his life at the age of forty-four. There is much that is interesting in his biography, which is largely made up of his correspondence, and which has been admirably edited by the accomplished author of "Tom Brown's School-days." The book is interesting chiefly as a personal delineation with no ambitious effort to point a moral, and for this reason it will be chiefly prized by the numerous friends and acquaintances of the publisher, many of whom were much attached to him. There are, however, many reminiscences of books and authors in the volume, that will be appreciated by the lovers of literature.

author of this book, who had devoted himself with might and main to the great unselfish work of human progress in Virginia, was burned out there, and, as he alleges, much persecuted by the bigotry of that benighted community. So he has produced this volume of poems, and gets such living as he can by the sale of it. Regarding the book, Mr. Whittier wrote to the author (1877): "I have to thank thee for thy note with the inclosed poems. Their humanitarian tone is excellent." Mr. Longfellow (1880) said: "I have read the poems with interest, and coincide with Mr. Whittier in his opinion of their merits." In the presence of such authorities it would be equally presuming and superfluous for us to express an opinion; but, as far as we are competent to judge, we agree with the illustrious New England poets in their estimate of this performance.

is a part of a series of reports made in connection with the work of the Census Bureau, concerning the water-powers of the whole United States, and relates to the rivers entering the Atlantic Ocean south of James River. Reviewing the